Update dependency Octokit to v9

This PR contains the following updates:

Package	Type	Update	Change
Octokit	nuget	major	`8.1.1` -> `9.0.0`

Release Notes

octokit/octokit.net (Octokit)

### [`v9.0.0`](https://togithub.com/octokit/octokit.net/releases/tag/v9.0.0) #### What's Changed ##### Breaking changes - Removes the .NET 5.0 support by [@nickfloyd](https://togithub.com/nickfloyd) in [https://github.com/octokit/octokit.net/pull/2806](https://togithub.com/octokit/octokit.net/pull/2806) ##### Features - \[feat]: Add RenameBranch method to RepositoryBranchesClient by [@dirtygooback](https://togithub.com/dirtygooback) in [https://github.com/octokit/octokit.net/pull/2799](https://togithub.com/octokit/octokit.net/pull/2799) ##### Fixes - (fix) RepositoryContentsClient.GetArchive does not return the expected binary content by [@Jericho](https://togithub.com/Jericho) in [https://github.com/octokit/octokit.net/pull/2803](https://togithub.com/octokit/octokit.net/pull/2803) ##### Maintenance - build(deps): bump xunit.runner.visualstudio from 2.5.1 to 2.5.3 by [@dependabot](https://togithub.com/dependabot) in [https://github.com/octokit/octokit.net/pull/2805](https://togithub.com/octokit/octokit.net/pull/2805) - build(deps): bump xunit from 2.5.1 to 2.5.3 by [@dependabot](https://togithub.com/dependabot) in [https://github.com/octokit/octokit.net/pull/2804](https://togithub.com/octokit/octokit.net/pull/2804) #### New Contributors - [@Jericho](https://togithub.com/Jericho) made their first contribution in [https://github.com/octokit/octokit.net/pull/2803](https://togithub.com/octokit/octokit.net/pull/2803) **Full Changelog**: https://github.com/octokit/octokit.net/compare/v8.1.1...v9.0.0